Defeating the Silent Enemy: Antimicrobial Resistance Looming as the Next Global Pandemic.

Antibiotics are the magic bullets that have saved millions worldwide. Enormous and irresponsible use of antibiotics has led to resistance to antibiotics, which is a matter of global health concern. The superbugs are responsible for life-threatening infections, treatment failure, and high mortality worldwide. The urgent healthcare threat caused by antimicrobial resistance (AMR) to nonfermenting gram-negative bacteria is being increasingly acknowledged worldwide. Antibiotic resistance found in organisms in hospital settings is now increasingly found in the community. Although antimicrobial stewardship requiring a multidisciplinary approach is developing rapidly at the hospital level, it needs more attention at the community level. New therapeutics are certainly required, but the major challenge is rapidly identifying resistant infections and tailoring treatment. This review highlights the crisis that reflects the current scenario of AMR, common resistant pathogens, and the major challenges in the fight against AMR. It also discusses potential methods and strategies to address the intricacies of antibiotic resistance.

Edema India: Executive Summary of Screening, Diagnosis, and Management of Edema.

The management of edema requires a systematic approach to screening, diagnosis, and treatment, with an essential initial assessment to differentiate between generalized and localized edema. The Association of Physicians of India (API) aimed to develop the first Indian Edema Consensus (Edema India), offering tailored recommendations for screening, diagnosing, and managing edema based on the insights from the expert panel. The panel suggested when evaluating edema symptoms, important factors to consider include the patient's current illness, medical history, risk factors, family history, and medications. Key diagnostic investigations for edema include complete blood count, cardiovascular imaging and markers, deep vein thrombosis (DVT) assessment, along with renal, hepatic, and thyroid function tests. Edema management involves a combination of pharmacologic and nonpharmacologic interventions, including limb elevation, physiotherapy, compression therapy, fluid removal, diuretics (loop diuretics: first-line therapy), and a sodium-restricted diet. The panel believed that educating patients could foster a preventive mindset, helping to prevent the worsening of edema.

Need for Uniformity in Clinical Teachings from Global Perspective.

How to cite this article: Saraf AA. Need for Uniformity in Clinical Teachings from Global Perspective. J Assoc Physicians India 2023;71(9):11-12.

Clinical Practice Guidelines for Management of Pain, Agitation, Delirium, Immobility, and Sleep Disturbance in the Intensive Care Unit: The ABCDEF Bundle.

It is crucial to prevent and manage intensive care unit (ICU) distress caused by a pentad of pain, agitation, delirium, immobility, and sleep disturbance (PADIS) to optimize immediate and longterm recovery and outcomes of critically ill patients. This clinical practice guideline provides an update on the prevention, management, and liberation of PADIS in adult ICU patients using an integrated, evidence-based, multidisciplinary ICU protocol: the ABCDEF bundle. ABCDEF bundle incorporates assessment, prevention, and management of pain; both spontaneous awakening trial (SAT) and spontaneous breathing trial (SBT); choice of sedation and analgesia; delirium: assessment, prevention and management, and early mobility and exercise; family involvement and empowerment (ABCDEF) together as a PADIS care bundle. This is a multidimensional ICU liberation bundle which is a patient-oriented, holistic team approach to the management of critically ill patients aimed at reducing ICU distress and immediate and long-lasting consequences of PADIS.

Video Call-based Fitness Assessment shows Poor Fitness in People with Type II Diabetes: Findings from Diabefly Digital Therapeutics Program.

OBJECTIVE: Exercise and physical activity are integral aspects for the effective management of diabetes. Unsupervised home exercise although very accessible is limited by poor adherence, risk of injury, and a higher dropout rate of participants. A fitness assessment by a qualified physiotherapist can help in understanding the baseline fitness of individuals and thus generating appropriate exercise prescriptions. The current study assesses the feasibility of video call-based fitness assessment for people with diabetes. The study also assesses the effect of current physical activity status and pain on performance in physical fitness tests. METHODS: One hundred participants with type II diabetes (T2D) underwent 6-minute walk test (6MWT), 1-minute push-up test, wall sit test, 1-minute sit-up test, and V-sit and reach test for measuring different components of physical fitness such as aerobic capacity, upper body strength, lower body strength, core strength, and flexibility, respectively. The performance in physical fitness of participants was analyzed after the video consult along with pain complaints and current exercise status. RESULTS: All the participants underwent the physical fitness test safely based on video call. Out of all the participants, a good range score was achieved by 52% in 6MWT, 17% in push-up test, 1% in wall sit test, 6% in sit-up test, and 9% in V-sit and reach test. Current physical activity status (aerobic exercise for minimum 20 minutes) did not show any association with performance in fitness tests (p = 0.89 for push-up test, p = 0.50 for wall sit test, p = 0.23 for sit-up test, and p = 0.10 for V-sit and reach test). Presence of upper body and lower body pain affected the performance in push-up test and wall sit test with 71.4% and 95.6% of participants achieving scores in poor to below-average range (p-value < 0.001). CONCLUSION: The study showed the safety and feasibility of conducting video call-based assessment of physical fitness by physiotherapists. The study also highlighted the poor glycemic control, high cardiovascular risk, and poor level of physical fitness in people with diabetes in India. Insights based on physical fitness, current physical activity status, and pain can help in developing personalized exercise plans for people with diabetes.

Overexpression of the type 1 adenylyl cyclase in the forebrain leads to deficits of behavioral inhibition.

The type 1 adenylyl cyclase (AC1) is an activity-dependent, calcium-stimulated adenylyl cyclase expressed in the nervous system that is implicated in memory formation. We examined the locomotor activity, and impulsive and social behaviors of AC1+ mice, a transgenic mouse strain overexpressing AC1 in the forebrain. Here we report that AC1+ mice exhibit hyperactive behaviors and demonstrate increased impulsivity and reduced sociability. In contrast, AC1 and AC8 double knock-out mice are hypoactive, and exhibit increased sociability and reduced impulsivity. Interestingly, the hyperactivity of AC1+ mice can be corrected by valproate, a mood-stabilizing drug. These data indicate that increased expression of AC1 in the forebrain leads to deficits in behavioral inhibition.

Phosphorylation of eukaryotic translation initiation factor 4E and eukaryotic translation initiation factor 4E-binding protein (4EBP) and their upstream signaling components undergo diurnal oscillation in the mouse hippocampus: implications for memory persistence.

Translation of mRNA plays a critical role in consolidation of long-term memory. Here, we report that markers of initiation of mRNA translation are activated during training for contextual memory and that they undergo diurnal oscillation in the mouse hippocampus with maximal activity observed during the daytime (zeitgeber time 4-8 h). Phosphorylation and activation of eukaryotic translation initiation factor 4E (eIF4E), eIF4E-binding protein 1 (4EBP1), ribosomal protein S6, and eIF4F cap-complex formation, all of which are markers for translation initiation, were higher in the hippocampus during the daytime compared with night. The circadian oscillation in markers of mRNA translation was lost in memory-deficient transgenic mice lacking calmodulin-stimulated adenylyl cyclases. Moreover, disruption of the circadian rhythm blocked diurnal oscillations in eIF4E, 4EBP1, rpS6, Akt, and ERK1/2 phosphorylation and impaired memory consolidation. Furthermore, repeated inhibition of translation in the hippocampus 48 h after contextual training with the protein synthesis inhibitor anisomycin impaired memory persistence. We conclude that repeated activation of markers of translation initiation in hippocampus during the circadian cycle might be critical for memory persistence.

Genetic disruption of the core circadian clock impairs hippocampus-dependent memory.

Perturbing the circadian system by electrolytically lesioning the suprachiasmatic nucleus (SCN) or varying the environmental light:dark schedule impairs memory, suggesting that memory depends on the circadian system. We used a genetic approach to evaluate the role of the molecular clock in memory. Bmal1-/- mice, which are arrhythmic under constant conditions, were examined for hippocampus-dependent memory, LTP at the Schaffer-collateral synapse, and signal transduction activity in the hippocampus. Bmal1-/- mice exhibit impaired contextual fear and spatial memory. Furthermore, LTP in hippocampal slices from Bmal1-/- mice is also significantly decreased relative to that from wild-type mice. Activation of Erk1,2 MAP kinase (MAPK) during training for contextual fear memory and diurnal oscillation of MAPK activity and cAMP in the hippocampus is also lost in Bmal1-/- mice, suggesting that the memory defects are due to reduction of the memory consolidation pathway in the hippocampus. We conclude that critical signaling events in the hippocampus required for memory depend on BMAL1.

Sclerotherapy as a Primary or Salvage Procedure For Aneurysmal Bone Cyst: A Case Report.

Introduction: A benign and locally aggressive tumour, aneurysmal bone cysts (ABCs) can develop in any bone but are more common in the metaphysis of long bones. Case Report: A 10 year old Female patient arrived at our outpatient department two years ago with a history of recurring discomfort, edema, and limited movement in her right shoulder and proximal 1/3 of her right arm. X-ray and Magnetic Resonance Imaging (MRI) of the humerus was performed and was diagnosed as aneurysmal bone cyst of proximal humerus. Patient was managed with sclerotherapy with polidocanol injections. The patient experienced significant symptoms improvement was seen two months after starting treatment, and there were no post operative side effects. Monthly progress reports were started, and after three months, physiotherapy was added to improve shoulder range of motion because there were no indications of a recurrence. A two-year follow-up showed improvement and no indications of a relapse. Conclusion: Percutaneous Sclerotherapy can be used as a primary procedure for aneurysmal bone cyst.

Medial surface plating of posterior column through the anterior intrapelvic approach in acetabulum fractures with involvement of both columns.

Aims: Posterior column plating through the single anterior approach reduces the morbidity in acetabular fractures that require stabilization of both the columns. The aim of this study is to assess the effectiveness of posterior column plating through the anterior intrapelvic approach (AIP) in the management of acetabular fractures. Methods: We retrospectively reviewed the data from R G Kar Medical College, Kolkata, India, from June 2018 to April 2023. Overall, there were 34 acetabulum fractures involving both columns managed by medial buttress plating of posterior column. The posterior column of the acetabular fracture was fixed through the AIP approach with buttress plate on medial surface of posterior column. Mean follow-up was 25 months (13 to 58). Accuracy of reduction and effectiveness of this technique were measured by assessing the Merle d'Aubigné score and Matta's radiological grading at one year and at latest follow-up. Results: Immediate postoperative radiological Matta's reduction accuracy showed anatomical reduction (0 to 1 mm) in 23 cases (67.6%), satisfactory (2 to 3 mm) in nine (26.4%), and unsatisfactory (> 3 mm) in two (6%). Merle d'Aubigné score at the end of one year was calculated to be excellent in 18 cases (52.9%), good in 11 (32.3%), fair in three (8.8%), and poor in two (5.9%). Matta's radiological grading at the end of one year was calculated to be excellent in 16 cases (47%), good in nine (26.4%), six in fair (17.6%), and three in poor (8.8%). Merle d'Aubigné score at latest follow-up deteriorated by one point in some cases, but the grading remained the same; Matta's radiological grading at latest follow-up also remained unchanged. Conclusion: Stabilization of posterior column through AIP by medial surface plate along the sciatic notch gives good stability to posterior column, and at the same time can avoid morbidity of the additional lateral window.

An Omicron-specific, self-amplifying mRNA booster vaccine for COVID-19: a phase 2/3 randomized trial.

Here we conducted a multicenter open-label, randomized phase 2 and 3 study to assess the safety and immunogenicity of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron-specific (BA.1/B.1.1.529), monovalent, thermostable, self-amplifying mRNA vaccine, GEMCOVAC-OM, when administered intradermally as a booster in healthy adults who had received two doses of BBV152 or ChAdOx1 nCoV-19. GEMCOVAC-OM was well tolerated with no related serious adverse events in both phase 2 and phase 3. In phase 2, the safety and immunogenicity of GEMCOVAC-OM was compared with our prototype mRNA vaccine GEMCOVAC-19 (D614G variant-specific) in 140 participants. At day 29 after vaccination, there was a significant rise in anti-spike (BA.1) IgG antibodies with GEMCOVAC-OM (P < 0.0001) and GEMCOVAC-19 (P < 0.0001). However, the IgG titers (primary endpoint) and seroconversion were higher with GEMCOVAC-OM (P < 0.0001). In phase 3, GEMCOVAC-OM was compared with ChAdOx1 nCoV-19 in 3,140 participants (safety cohort), which included an immunogenicity cohort of 420 participants. At day 29, neutralizing antibody titers against the BA.1 variant of SARS-CoV-2 were significantly higher than baseline in the GEMCOVAC-OM arm (P < 0.0001), but not in the ChAdOx1 nCoV-19 arm (P = 0.1490). GEMCOVAC-OM was noninferior (primary endpoint) and superior to ChAdOx1 nCoV-19 in terms of neutralizing antibody titers and seroconversion rate (lower bound 95% confidence interval of least square geometric mean ratio >1 and difference in seroconversion >0% for superiority). At day 29, anti-spike IgG antibodies and seroconversion (secondary endpoints) were significantly higher with GEMCOVAC-OM (P < 0.0001). These results demonstrate that GEMCOVAC-OM is safe and boosts immune responses against the B.1.1.529 variant. Clinical Trial Registry India identifier: CTRI/2022/10/046475 .

Do age, gender, BMI and disease duration influence the clinical outcomes in patients of knee osteoarthritis treated with serial injections of autologous platelet rich plasma?

Purpose: To study whether age, gender, body mass index(BMI) and disease duration influence the clinical outcomes in kellgren-Lawrence(K-L) grade II,III knee osteoarthritis(KOA) patients treated with serial injections of platelet rich plasma(PRP). Patients and methods: 65 patients were given three monthly intra-articular injections of PRP in this prospective interventional study. The patients were divided into subgroups depending on the factor studied: by age(in years) into young <45(n = 7), middle age 45-60(n = 35), and elderly >60(n = 23): by BMI(in kg/m2) into; normal <25(n = 25), overweight 25-30(n = 27) and obese >30(n = 13) and disease duration; less(n = 32) or more than 1 year(n = 33) symptom duration. Visual analogue scale (VAS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) were used as outcome measures and assessed before each injection and then at 6 and 9 months post injection. Groups were homogenous with respect to baseline characteristics. Results: Mean VAS and WOMAC scores showed a statistically significant improvement (P < 0.0001) across all groups and subgroups (age,gender,BMI,disease duration) at follow up. On intra-subgroup comparison, we found no significant differences(P > 0.05) among age, BMI or gender subgroups, however the scores were significantly better in patients with disease duration of less than 1 year than those with more than 1 year duration at both 6 and 9 months[P < 0.001(RC = 9.630,95% CI = 4.037-15.222,P = 0.001)]. Conclusion: PRP injections if given serially can improve the short term subjective scores of VAS and WOMAC scores in patients with K-L grade II and III KOA irrespective of age, gender, BMI or disease duration, however, clinical benefits can be maximized if given early in the disease course.

Serial intraarticular injections of growth factor concentrate in knee osteoarthritis: A placebo controlled randomized study.

Objective: To evaluate and compare clinical efficacy and effect on specific serum biomarker with serial injections of growth factor concentrate (GFC) for knee osteoarthritis (KOA) in a randomized triple blinded placebo controlled interventional study. Methods: Final assessment was done on 58 patients. Patients with Kellgren-Lawrence grade II, III knee osteoarthritis were administered monthly intraarticular injections(3 injections) of GFC(n = 31) or saline(n = 27) and evaluated clinically with visual analogue scale(VAS) and Western Ontario and McMaster Universities Arthritis Index(WOMAC) at 3,6 and 12 months post therapy. Biochemical analysis was done with serum biomarker of cartilage degeneration, Collagen 2-1 (Coll2-1), estimated at baseline and at final follow up. Results: Both the groups exhibited statistically significant improvements (P < 0.05) in VAS at 3,6 and 12 months. WOMAC improvement reached statistical significance for GFC group at every evaluation (P < 0.001) but only at 12 months in NS group (P = 0.029). The improvements were clinically meaningful only in GFC group throughout follow up (Minimal clinically important differences >12% of baseline in WOMAC and >2 cm difference in mean for VAS). Intergroup comparison revealed GFC to be much better for both scores at every evaluation (95% CI of 0.2-1.5,[P = 0.008], 1.4-2.9,[P < 0.0001], and 2.7-4.2,[P < 0.0001] for VAS, 7.3-16.0 [P < 0.001], 11.6-21.9 [P < 0.001] and 18.1-31.1[P < 0.001] for WOMAC). Statistically significant decrease in serum Coll2-1 levels were observed for GFC group only. No serious complications were seen. Conclusion: Serial(three) monthly GFC injections result in clinically meaningful improvement of subjective pain and function outcome scores, sustaining up to 12 months in KOA grade II and III. GFC also lead to significant reduction in serum levels of cartilage degradation biomarker coll2-1.

Transforaminal Injections of Platelet-Rich Plasma Compared with Steroid in Lumbar radiculopathy: A Prospective, Double-Blind Randomized Study.

Purpose: To evaluate and compare the clinical efficacy of transforaminal steroid and platelet-rich plasma (PRP) injections in patients with discogenic lumbar radiculopathy. Methods: 60 patients were randomized to be treated with single transforaminal injection of PRP (n = 29) or steroid (methylprednisolone acetate [n = 31]). Clinical assessment was done with Visual analogue scale (VAS), modified Oswestry low back pain disability index (MODI), and straight leg raise test (SLRT). Baseline assessment of outcomes was done followed by post-intervention evaluation at 1, 3, and 6 months. Both groups had similar baseline characteristics. Results: There was a significant statistical improvement of VAS and MODI in both groups at follow-up (P < 0.05). In PRP group, minimal clinically important change (> 2 cm difference of mean for VAS and > 10-point change in MODI) for both outcome scores was achieved at all follow-up intervals (1, 3, 6 months), while as in steroid group, it was seen only at 1 and 3 months for both VAS and MODI. On intergroup comparison, better results were seen in steroid group at 1 month (P < 0.001 for both VAS and MODI), and in PRP group at 6 months (P < 0.001 for both VAS and MODI) with non-significant difference at 3 months (P = 0.605 for MODI and P = 0.612 for VAS). More than 90% tested SLRT negative in PRP group and 62% in steroid group at 6 months. No serious complications were seen. Conclusion: Transforaminal injections of PRP and steroid improve short-term (up to 3 months) clinical outcome scores in discogenic lumbar radiculopathy, but clinically meaningful improvements sustaining for 6 months were provided by PRP only.

Fitterfly Diabetes CGM Digital Therapeutics Program for Glycemic Control and Weight Management in People With Type 2 Diabetes Mellitus: Real-world Effectiveness Evaluation.

BACKGROUND: Digital therapeutic platforms facilitate health care through patient-centered strategies based on multidisciplinary teams and shared decision-making. Such platforms can be used for developing a dynamic model of diabetes care delivery, which can help in improving glycemic control by promoting long-term behavior changes in people with diabetes. OBJECTIVE: This study aims to evaluate the real-world effectiveness of the Fitterfly Diabetes CGM digital therapeutics program for improving glycemic control in people with type 2 diabetes mellitus (T2DM) after the completion of 90 days in the program. METHODS: We analyzed deidentified data of 109 participants in the Fitterfly Diabetes CGM program. This program was delivered through the Fitterfly mobile app coupled with continuous glucose monitoring (CGM) technology. This program consists of 3 phases: the first phase is observation, wherein the patient's CGM readings are observed for 7 days (week 1); the second phase is the intervention; and the third phase aims at sustaining the lifestyle modification introduced during the second phase. The primary outcome of our study was the change in the participants' hemoglobin A1c (HbA1c) levels after program completion. We also evaluated the changes in participant weight and BMI after the program, changes in the CGM metrics in the initial 2 weeks of the program, and the effects of participant engagement in the program on improving their clinical outcomes. RESULTS: At the end of the 90 days of the program, the mean HbA1c levels, weight, and BMI of the participants were significantly reduced by 1.2% (SD 1.6%), 2.05 (SD 2.84) kg, and 0.74 (SD 1.02) kg/m2 from baseline values of 8.4% (SD 1.7%), 74.45 (SD 14.96) kg, and 27.44 (SD 4.69) kg/m2 in week 1, respectively (P<.001). The average blood glucose levels and time above range values showed a significant mean reduction by 16.44 (SD 32.05) mg/dL and 8.7% (SD 17.1%) in week 2 from week 1 baseline values of 152.90 (SD 51.63) mg/dL and 36.7% (SD 28.4%), respectively (P<.001 for both). Time in range values significantly improved by 7.1% (SD 16.7%) from a baseline value of 57.5% (SD 25%) in week 1 (P<.001). Of all the participants, 46.9% (50/109) showed HbA1c reduction ≥1% and 38.5% (42/109) showed weight loss ≥4%. The average number of times the mobile app was opened by each participant during the program was 108.80 (SD 127.91) times. CONCLUSIONS: Our study shows that participants in the Fitterfly Diabetes CGM program showed a significant improvement in their glycemic control and reduction in weight and BMI. They also showed a high level of engagement with the program. Weight reduction was significantly associated with higher participant engagement with the program. Thus, this digital therapeutic program can be considered as an effective tool for improving glycemic control in people with T2DM.

Serial Platelet-Rich Plasma Intra-articular Injections in Kellgren and Lawrence Grade IV Knee Joint Osteoarthritis: A Prospective Blinded Placebo-Controlled Interventional Study.

Purpose: The purpose of this study was to evaluate whether serial intra-articular (IA) Platelet-Rich Plasma (PRP) injections improve pain and function in patients of Kellgren-Lawrence (K-L) Grade IV primary knee osteoarthritis (KOA), not willing for arthroplasty or having relative contraindications to surgery. Methods: 90 patients (84 available at final follow-up) of Grade IV KOA were given 3 PRP or Normal Saline injections at 1-month interval. Pain and functional assessment was done with Visual analog scale (VAS) and Western Ontario and McMaster universities osteoarthritis index (WOMAC) respectively, at baseline and then at three and six months of follow-up. Both groups were homogenous with similar baseline characteristics. Results: Both groups showed statistically significant improvements in the outcome scores but only PRP showed minimal clinically important difference (25% in WOMAC and > 2 cm difference of mean in VAS at follow-up). For inter-group comparison, PRP showed better results as there was statistically significant difference in WOMAC at 3 months (Difference = - 9.220, 95% CI = - 13.1945 to - 5.2455, P < 0.0001) and at 6 months (Difference = - 10.360, 95% CI = - 14.5358 to - 6.1842, P < 0.0001). Similar results were seen for VAS also (Difference = - 0.580, 95% CI = - 1.1412 to - 0.0188, P = 0.04 at 3 months, Difference = - 0.870, 95% CI - 1.3993 to - 0.3407, P = 0.001 at 6 months). Outcome scores significantly correlated with age and sex but not with body mass index (BMI). Conclusion: Serial Intra-articular Injections of autologous PRP mildly improve short-term subjective pain and knee function scores in patients of Grade IV KOA without any major complications.

Molecular determinants for PP2A substrate specificity: charged residues mediate dephosphorylation of tyrosine hydroxylase by the PP2A/B' regulatory subunit.

Together with protein phosphatase 1, protein phosphatase 2A (PP2A) contributes the bulk of Ser/Thr phosphatase activity in most cell types. The predominant form of PP2A is a heterotrimer of catalytic (C), scaffolding (A), and diverse regulatory subunits (B, B', and B''). We have previously shown that N-terminal phosphorylation sites in tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis, are specifically dephosphorylated by PP2A holoenzymes containing the B'beta regulatory subunit. Here, we identify a Glu residue conserved in B' regulatory subunits that is critical for dephosphorylation and inactivation of tyrosine hydroxylase in vitro and in PC12 cells. According to the PP2A heterotrimer crystal structure, Glu153 (B'beta numbering) abuts the catalytic site on the C subunit, and we demonstrate that Glu153 substitution inhibits multisite TH dephosphorylation without compromising PP2A/B'beta holoenzyme assembly or in vitro dephosphorylation of model substrates. Apart from its role in modulating TH activity, Glu153 is also necessary for PP2A/B'beta-mediated enhancement of nerve growth factor signaling. Furthermore, global phosphoproteome analysis suggests that Glu153 mediates dephosphorylation of most B'beta substrates in PC12 cells. With regard to selectivity determinants in the substrate, we show that B'beta Glu153 recognizes Arg37 and Arg38 in TH to direct dephosphorylation of both upstream (Ser31) and downstream (Ser40) sites. These results provide evidence of a subunit-spanning substrate docking site on the PP2A/B' holoenzyme, in which negatively charged side chains in the regulatory subunit interact with positive charges proximal to phosphorylated residues to mediate site-specific dephosphorylation.

The 48-kDa alternative translation isoform of PP2A:B56epsilon is required for Wnt signaling during midbrain-hindbrain boundary formation.

Alternative translation is an underappreciated post-transcriptional regulation mechanism. Although only a small number of genes are found to be alternatively translated, most genes undergoing alternative translation play important roles in tumorigenesis and development. Protein phosphatase 2A (PP2A) is involved in many cellular events during tumorigenesis and development. The specificity, localization, and activity of PP2A are regulated by B regulatory subunits. B56epsilon, a member of the B56 regulatory subunit family, is involved in multiple signaling pathways and regulates a number of developmental processes. Here we report that B56epsilon is alternatively translated, leading to the production of a full-length form and a shorter isoform that lacks the N-terminal 76 amino acid residues of the full-length form. Alternative translation of B56epsilon occurs through a cap-dependent mechanism. We provide evidence that the shorter isoform is required for Wnt signaling and regulates the midbrain/hindbrain boundary formation during Xenopus embryonic development. This demonstrates that the shorter isoform of B56epsilon has important biological functions. Furthermore, we show that the N-terminal sequence of B56epsilon, which is not present in the shorter isoform, contains a nuclear localization signal, whereas the C terminus of B56epsilon contains a nuclear export signal. The shorter isoform, which lacks the N-terminal nuclear localization signal, is restricted to the cytoplasm. In contrast, the full-length form can be localized to the nucleus in a cell type-specific manner. The finding that B56epsilon is alternatively translated adds a new level of regulation to PP2A holoenzymes.

Differential expression of the B'beta regulatory subunit of protein phosphatase 2A modulates tyrosine hydroxylase phosphorylation and catecholamine synthesis.

Tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis, is stimulated by N-terminal phosphorylation by several kinases and inhibited by protein serine/threonine phosphatase 2A (PP2A). PP2A is a family of heterotrimeric holoenzymes containing one of more than a dozen different regulatory subunits. In comparison with rat forebrain extracts, adrenal gland extracts exhibited TH hyperphosphorylation at Ser(19), Ser(31), and Ser(40), as well as reduced phosphatase activity selectively toward phosphorylated TH. Because the B'beta regulatory subunit of PP2A is expressed in brain but not in adrenal glands, we tested the hypothesis that PP2A/B'beta is a specific TH phosphatase. In catecholamine-secreting PC12 cells, inducible expression of B'beta decreased both N-terminal Ser phosphorylation and in situ TH activity, whereas inducible silencing of endogenous B'beta had the opposite effect. Furthermore, PP2A/B'beta directly dephosphorylated TH in vitro. As to specificity, other PP2A regulatory subunits had negligible effects on TH activity and phosphorylation in situ and in vitro. Whereas B'beta was highly expressed in dopaminergic cell bodies in the substantia nigra, the PP2A regulatory subunit was excluded from TH-positive terminal fields in the striatum and failed to colocalize with presynaptic markers in general. Consistent with a model in which B'beta enrichment in neuronal cell bodies helps confine catecholamine synthesis to axon terminals, TH phosphorylation was higher in processes than in somata of dopaminergic neurons. In summary, we show that B'beta recruits PP2A to modulate TH activity in a tissue- and cell compartment specific fashion.

Non-adenine based purines accelerate wound healing.

Wound healing is a complex sequence of cellular and molecular processes that involves multiple cell types and biochemical mediators. Several growth factors have been identified that regulate tissue repair, including the neurotrophin nerve growth factor (NGF). As non-adenine based purines (NABPs) are known to promote cell proliferation and the release of growth factors, we investigated whether NABPs had an effect on wound healing. Full-thickness, excisional wound healing in healthy BALB/c mice was significantly accelerated by daily topical application of NABPs such as guanosine (50% closure by days 2.5-2.8). Co-treatment of wounds with guanosine plus anti-NGF reversed the guanosine-promoted acceleration of wound healing, indicating that this effect of guanosine is mediated, at least in part, by NGF. Selective inhibitors of the NGF-inducible serine/threonine protein kinase (protein kinase N), such as 6-methylmercaptopurine riboside abolished the acceleration of wound healing caused by guanosine, confirming that activation of this enzyme is required for this effect of guanosine. Treatment of genetically diabetic BKS.Cg-m+/+lepr db mice, which display impaired wound healing, with guanosine led to accelerated healing of skin wounds (25% closure by days 2.8-3.0). These results provide further confirmation that the NABP-mediated acceleration of cutaneous wound healing is mediated via an NGF-dependent mechanism. Thus, NABPs may offer an alternative and viable approach for the treatment of wounds in a clinical setting.